Auto copy paper and methods of making the same



Feb. 26, 1963 J. c. CORTEZ 3,079,270

AUTO COPY PAPER AND METHODS OF MAKING THE SAME Filed March 6. 1959 5Sheets-Sheet. 1

/ Coating modified Sheet uncoated White ink Black paper G Coatingmodified colored ink Sheet uncaated White paper FIG.2

Paper sheet for writing Transparent sheet Copy sheet of F|G.Ior2

FIG.3

1 o l e Transparent A Coating Opaque sheet 3 j modified ink INVENTOR.Jose C.Cortez ATTORNEYS Feb. 26, 1963 J. c. coRTEz ,0

AUTO COPY PAPER AND METHODS OF MAKING THE SAME I Filed March 6, 1959 5Sheets-Sheet. 2

Green modified ink Red rnodified ink Blue modified ink Block modifiedink Sheet unoooted white G 5 Coofjng of white I modified Ink Sheetprinted in different colors with unmodified ink 6 Colored coating ofmodified ink Uncooted underlylng sheet uvvvrorr. Jose C. CortezATTORNEYS.

Feb. 26, 1963 J. c. CORTEZ 3,079,270

AUTO COPY PAPER AND METHODS OF MAKING THE SAME Filed March 6. 1959 v 3Sheets-Sheet. 3

Green modified ink Red modified ink Black modified ink Green unmodifiedink Red unmodified ink a F|G.8

Protective coating contrasting color Coating modified ink Transparentsheet F I 9 Auto copy coating on top surface. Transfer coating on undersurface Uncoated paper Uncoated paper FIGJO INVENTOR. Jose C. CortezATTORNEYS tats it i

This application relates to improvements in copy papers and methods ofmaking the same, and is a continuation in part of my pendingapplications Ser. No. 242,841, filed August 21, 1951, and Serial No.340,141, filed March 3, 1953, both now abandoned. Copy papers of thecharacter to which this invention relates are termed auto copy papersand are employed for making a number of copies of an inscribed ortypewritten manuscript simultaneously without the use of a carbon orlike sheet interleaved with the several sheets upon which the duplicaterecords are made.

For many years a great deal of effort has been expended in thedevelopment of auto copy papers in an attempt to do away with the use ofcarbon copy paper which has a number of well recognized drawbacks whichneed not be recited here. However, notwithstanding this veryconsiderable effort heretofore expended in an attempt to produce asatisfactory copy paper, the great majority of duplicate copies that areproduced simultaneously with the writing of the original are carboncopies made with interleaved sheets upon which the copies are made or bya layer of carbon on the backs of the overlying sheets.

Of the many types of auto copy papers heretofore proposed the mostsuccessful consists of a sheet of colored pa er having a surface coatingof translucent wax or similar material which is rendered transparent bythe compression resulting from the typewriter key, or by the pressure ofa pen or stylus, to thereby make the underlying colored surface of thepaper visible in the areas corresponding to the letters printed ormarked on the uppermost sheet. Wax sheets are, however, open to a numberof objections. The coatings heretofore used have low m lting points andtend to blur and become opaquein the area of the markings when subjectedto temperatures but little above the ordinary room temperature. Thecompositions heretofore used are damaged by water. Although notwater-soluble in the usual sense, they are water-absorbent to such anextent that the record is liable to be destroyed if the sheets aresubjected to undue dampness. Sheets with coatings such as heretoforeused are considerably thicker than the ordinary paper used for duplicatecopies, thereby reducing the number of copies that may be made. In fact,the commercial wax type auto copy sheets now available are thicker thanthe combined carbton and copy sheet which would otherwise be used, andare also stiffer and less capable of transmitting pressure through alimited area to an underlying sheet of like character, with the resultthat the number of legible copies that may be produced at a singlewriting is very limited.

A further defect in the copy papers of the prior art is that the coatingof the sheets with the composition heretofore used can be carried outonly on slow speed machines as compared, for example, with a high speedprinting press, whereby the cost of the sheet is greatly increased overthat of an ordinary printed sheet such as used for making commercialforms of the type most generally employed for multiple copies.

The object of the present invention is to provide auto copy paper whichis in appearance and observable physical properties indistinguishablefrom ordinary coated paper of grades commonly used for making writingpaper,

ice

sales slips and the like, and which when used in an ordinary typewriteror tabulating machine will produce copies comparable to those producedby ordinary carbon paper. Coated printing papers are produced byapplying to the surface of the paper sheet a coating consistingessentially of pigment such as calcium carbonate and an adhesive such ascasein, the coating being applied either in a non-aqueous solvent by aprinting operation or in aqueous suspension by a paper coatingoperation. These coatings when applied to the paper sheet form acontinuous opaque film or layer adhering to the face of the paper sheetand providing a smooth surface for receiving the printed or typewrittenlegend.

In carrying out my invention I employ standard coating compositionscontaining sufiicient pigment to form opaque coatings on the face of thepaper and by the addition of substances which I have hereinafterdesignated as surface-active agents, I modify the characteristics of thecoating in such manner that under the impact of a typewriter key or thepressure of a stylus the continuity and opacity of the coating aredestroyed in the area impacted so as to reveal the surface of theunderlying paper sheet. The underlying paper sheet may be dyed or itssurface may be otherwise coated with a color contrasting with that ofthe pigmented coating so that in the impacted areas the surface of theunderlying web Will appear in a color contrasting with that of thesurrounding coated surface. The modification of the pigmented coating'by my invention does not significantly alter the appearance,flexibility, heat resistance, etc., of the coated sheet and my improvedauto-copy paper may be used and handled in precisely the same manner ascoated paper having conventional coatings which have not been modifiedby the addition of the so-called surface-active agent. Otherwise stated,the coating is a firm dye pigment coating of good ink receptivity, isnot tacky and does not smear.

Suitable coating materials having the characteristics above set forthmay be readily produced in the form of high speed printing inks byadding to such inks a surface-active agent such as diethylene glycolmonostearate, penta'erythritol tetrastearate, glyceryl monostearate andthe like or mixtures thereof, the amount of such surfaceactive agentbeing approximately the same as the quantity of pigment in the ink. Thequantity of surface-active agent required is not critical and the amountrequired for optimum results varies with the surface-active agentsemployed, the characteristics of the pigments used and also theviscosity of the ink, as well as the nature of the pigment-extenders,flattening agents, film-formers and the like which are used in printinginks to improve their printing qualities. Generally speaking, thegreater the quantity of surface-active agents employed in proportion tothe pigment content, the greater the number of copies that can be madewith the same machine operating in the same manner. Apparently as thepercentage of surfaceactive agent is decreased the greater the impactrequired to obtain the same results. If too much of the surfaceactiveagent is used the adherence of the coating to the surface may be soreduced that the paper will not withstand the handling required inmaking the record and in its subsequent use.

Printers ink in its broadest sense consists of pigment and a carrier inwhich the pigment is suspended, and a suitable coating material ormodified ink for producing my improved auto copy paper by a printingoperation may be produced by adding to the pigment suspension asurface-active agent having the characteristics of the compounds abovereferred to. Such coating materials are in effect modified inks and maybe applied in the same manner and by the same apparatus as theunmodified inks.

3 For example, a suitable modified white ink may be me pared accordingto the following formula:

Parts Diethylene glycol monostearate (Kesslers) 60 Mangnesium carbonateUSP light powder (Bakers)- 60 Ethylene dichloride (Jeffersons) 500 Theingredients may be mixed together at room temperature and stirred in ahigh speed mixer until a suitable suspension of the pigment andsurface-active agent in the carrier is obtained.

The following additional formulas have been found satisfactory for theproduction of modified inks of difierent colors for use in various typesof printing processes:

, Parts White 2: Diethylene glycol monost'earate 60 Magnesium carbonateUSP light 60 Low viscosity Parlon, 9 c.p.s Santocel C, sub-micro silica1 Ethylene dichloride 500 White 3: I V Diethylene glycol monopalmitate60 Magnesium carbonate USP light 60 Low viscosity polyclo rubberPliolite 1230--- 8 Ethyl alcohol anhydrous 100 Toluol pure 400 White 4:

Pentaerythritol tetrastearateuu, 60 Magnesium carbonate-USP light 60 Lowviscosity polyclo rubber Pliolite 1230-- 3 Ethyl alcohol anhydrous 100Toluol pure 400 Blue 5 jGlyceryl monomyristate 60 Victoria blue tonerdry 2 Peacock blu'e lake dry 58 Low viscosity polyclo rubber Pliolite1230...--- 8 Ethyl alcohol anhydrous 100 Toluol pure 40G Black 6:

Diethylene glycol monostearate 60 Lamp black 60 Low viscosity Parlon 9c.p.s- 8 Santocel C, sub-micro silica 2 Ethyl alcohol anhydrous; 100Toluol pure 400 Red 7:

Ethylene glycol monomyristate 60 Red toner phloxine, dry 30 Aluminatrihydrate dry; 30 Low viscosity Parlon 9 c.p.s u 6 Santocel C,sub-micro silica 2 Ethyl alcohol anhydrous 1G0 Toluol pure 400 When morethan one solvent is to be employed, it has been proven more practical tomix the solvents beforehand in order to make up one solvent out of thecombination, thus for example, the 100 parts of ethyl alcohol anhydrousand the 400 parts of toluol pure, specified in Formula 5 above, aremixed together to produce one solvent representing an 80-20 toluol-ethylalcohol solution. In like manner other solvent combinations can be made.With those facts in mind I prefer to place in the high speed shearmixer, about one-third of the solvent to which the corresponding portionof the flatting agent is added first; the resulting mixture is stirredfor about five minutes atthe end of which, while the mixer is'in motion,the corresponding portion of the film-forming agent is added withcontinuous stirring for about five minutes more before the incorporationof the pigment into this mixture is to be made. The pigment is thenadded little by'little while the mixer is in motion at high speed untila dough-like mass is'formed that allows proper and effi cient shearingaction by the mixer. Whenever this doughlike mass becomes too thick orheavy to allow proper shearing action, then suitable quantities of thesurface active agent are added to promote proper wetting action whichwill permit the further addition of pigment until all of the requiredquantityof the pigment called for by the specific formula has beenincorporated and an even doughlike mass has been formed that will allowuniform, efficient shearing action by the mixer. The shearing operationis continued for about a half hour at the end of which, the rest of thesurface-active agent is to be added, little by little until thedough-like mass becomes of the consistency of heavy cream; another halfhour of shearing is continued and then the rest of the solvent is addedslowly. The resulting mixture is then filtered through fine gauze andallowed to stand for six hours or more before applying the same byeither printing or coating operations.

1 Modified inks may be prepared for application by a particular highspeed printing press by selecting an ink which is suitable for operationin the press as an unmodified ink and modifyirn the ink by the additionof an appropriate quantity of a surface-active agent of the characterabove referred to. Satisfactory results will not ordinarily be obtainedby merely adding the surface-active agent to the already compounded ink,but suitable modified inks may be made by compounding the ingredientsmaking up the unmodified ink with the addition of the required amount ofthe surface-active agent and following the compounding proceduredescribed above. In so compounding the ink it may be desirable to varythe quantity of solvent used in order that the modified ink shall havethe same fluidity and drying characteristics as the unmodified ink.Itmay also be desirable to modify to a certain extent the flatteningagents, pigment extenders and other ingredients of the unmodified ink inorder for the modified ink to have precisely the same physicalproperties as the unmodified ink, but ordinarily an adjustment of thesolvent content of the ink and the addition Of the surface-active agentare the only formula changes required to produce a modified ink whichmay be substituted for the unmodified inkin the operation of the press.

By eliminating the volatile solvents entirely suitable coatingcompositions in the solid rather than in the liquid state can be madewith the same materials in suitable proportions, in the form of solid,low viscosity, high speed, modified thermo-fluid inks which dry or setby exposure to cold instead of heat, upon contacting a cool surface,suitable for application in a melted condition by high speed rotarypresses or by high speed, threeroll precision coaters having fountains,platens, metal rollers and forms specially heated above the meltingpoint of the inks, as commonly employed for printing with coldset inksor for high speed coating with hot-melts.

These modified thermo-fiuid, cold-set, high speed inks can bemanufactured simply by first melting in a steamjacketed mixing kettle,to a point of fluidity a small quantity of the surface-active agent towhich the corresponding quantity of the film-forming agent is then addedwith continuous stirring until the hot mixture reaches the consistencyof taffy, at which point, another more substantial quantity of thesurface-active agent is then added little by little withcontinuous-stirring until a completely homogenous mixture is therebyobtained. The corresponding quantity of the fiatting agent is then addedand incorporated into the mixture with vigorous, continuous stirring andthen, the rest of the corresponding quantity of the surface-active agentis finally added, little by little, with continuous vigorous stirringuntil a completely homogenous mixture is thereby again obtained. Thetemperature of the resulting mixture is now to beinaintained evenly at apoint well above the melting point of the surface-active agent, sayabout to degrees centigrade, at which point, the corresponding quantityof the pigment is incorporated little by little with vigorous continuousstirring until a completely homogenous pigmented mix-- ture is obtained.

During this stirring and mixing operation, the degree of dispersion ofthe pigment into the vehicle is tested several times by means of a stripof aluminum foil which is dipped into the hot mixture and cooling thesame by contacting a cool surface, for example, by Wrapping the inkedfoil around a glass filled with ice cubes and then examining the coatingwhen cold for evenness of pigment distribution or aggregates as the casemay be; continuous vigorous stirring is continued until a perfect, evencolored pigmented film is obtained on the aluminum foil. At this point,the steam or heat is shut off and the resulting mixture cooled down bycontinuous stirring until it reaches near to the solidification point.The resulting compound when cold is a solid which is broken intosuitable chips and the chips milled to the highest degree of finenessobtainable in order to attain the maximum degrees of dispersion of thepigment into the binding component. Such milling operations sometimesare more efficiently carried out by means of refrigerated mills such asthe ones commonly employed for the milling of synthetic resins and thelike. The resulting solid represents a thermo-fiuid, cold set modifiedhigh speed ink ready for use as previously described. Inks of the typereferred to above can be readily obtained from the following or likeformulas:

Black 1: Parts by Weight Ethylene glycol monomyristate 60 Ethyleneglycol monolaureate 10 Carbon black 25 Pliolite 1230 5 Blue 2:

Glyceryl monopalmitate 60 Glyceryl monococate l Peacock blue dry 25Pliolite 1230 White 3:

Diethylene glycol monostearate 60 Diethylene glycol monococate Zinceoxide French process 25 Low viscosity ethyl cellulose 5 The addition ofrelatively small quantities of suitable inert flatting agents such asSantocell C or Bentones l8 and 34, in the order of one-tenth to fivetenths of one percent of the total Weight of the ink, improveconsiderably all of the desirable physical properties of the thermofluidinks.

As previously stated, the compounds which I have at this time found tobe the most suitable for producing satisfactory auto copy papers arewater-insoluble, chemically inert, non-ionic surface-active agents.These compounds are the products of reactions between alcohols andothers of the polyhydric type, synthetic polyoxyalkylene condensates andthe fatty acids, either natural or synthetic, plain or modified byhydrogenation or oxygenation of varying carbon chain length, derivedfrom oils, fats, waxes, resins, oleoresins, gums, rosin and combinationsthereof. By reacting properly these materials innumerable variations ofmono, di, tri, etal. esters, esterethers, partial esters andcombinations thereof are obtained ranging from low freezing point oilyliquids at minus 16 degrees centigrade to relatively high melting solidsat 70 degrees centigrade and above.

The pigments included in the above examples are opaque pigments whichare customarily employed in producing inks of good hiding power forordinary printing operations. I may, however, by this procedure abovedescribed produce modified transparent inks such as ern ployed inmulti-color printing where one color is overlaid on another color toproduce the desired color effect. So far as I am personally aware, allthe pigments commonly employed in the manufacture of printing inks, bothopaque and transparent, may be suitably modified by the procedure abovedescribed.

The modified inks or coating compositions in the area impacted by thetypewriter key adhere to the back of the overlying sheet in someinstances, while in other cases the coating in the impacted area doesnot leave the paper but the continuity and opacity of the coating is soaltered that the surface of the underlying sheet is as fully revealed asin those instances where the pigment particles do adhere to theoverlying sheet. While it is not definitely known just why thisdifferent eflect takes place, it has been observed that when diethyleneglycol monostearate is used as the surface-active agent as in Example 2above, the back of the overlying sheet does not apparently pick up anyof the coating composition from the impacted areas, while coating madewith pentaerythritol tetrastearate will produce on the back of theoverlying sheet a clear replica in reverse of the record made on thecopy sheet.

This adherence of the coating composition to the back of the overlyingsheet may be prevented by treating the surface of the sheet with asuitable mold-releasing agent such as an organo silicon polymer, inwhich case the detached coating composition can be detected in the formof fine particles on the surface of the sheet from which they can beremoved by merely shaking the sheet.

Just why the substitution of pentaery-thritol tetrastearate fordiethylene glycol monostearate makes this difference in the behavior ofthe coatings is unknown, as the two coatings in appearance andobservable physical properties are the same.

The foregoing examples are for the most part modified inks for use inhigh speed printing presses as the use of such presses for theapplication of the modified inks to the surface of the paper isdesirable from the standpoint of economy of manufacture. However, asstated above, my invention is applicable to inks adapted primarily foruse in other types of printing apparatus. For example, presses of theso-called silk screen type may be successfully employed for themanufacture of auto copy paper in accordance with my invention. For suchpurpose an unmodified ink of the character employed in such presses maybe modified by the addition of a suitable amount of an appropriatesurface-active agent. As an example of a white ink for use in silkscreen presses the following formula has been found satisfactory:

Parts Diethylene glycol monostearate Magnesium carbonate 60 Crystalclear silk screen base (Sherwin-Williams) 45 Transparent silk screenbase (Sherwin-Williams) 15 Naphtha Ordinary printing inks consistingprimarily of opaque pigment suspended in a vehicle of an oleaginousnature such, for example, as linseed oil, may also be modified by theaddition of an appropriate quantity of a surfaceactive agent such asdiethylene glycol monostearate in the order of one pound ofsurface-active agent to each pound of pigment (dry basis).

Just what happens to the pigment particles in the impacted area whensheets coated in the manner above described are used as copy sheets in atypewriter is not fully known. The coating before the sheet is used is athin continuous opaque layer of oriented pigment particles adhering tothe surface of the underlying sheet and to some extent filling thespaces between the surface fibers of the sheet so that the surface ofthe coating is smoother than the surface of the paper web. By the impactof the typewriter keys the continuity and opacity of the pigment layerare altered, for the surface of the underlying sheet is plainly visiblein the areas impacted by the keys and the edges of characters are asclearly defined as the characters printed by the ink on the ribbon copy.

Sheets of uncoated paper dyed black having a thin coating of a whitemodified ink of the formula on page 13 above were used as copy sheets ina standard typewriter and then examined with reflected light under amicroscope at x magnification. The dyed fibers cases with starch.

equipment.

forming the surface of the underlying sheet were visible throughout thearea of the characters examined and fine white particles were scatteredover and apparently imbedded in the fibers. The crystal clear silkscreen base of this formula is an alkyd resin and the transparent silkscreen base is a combination of polymerized linseed oil and rosin oil.

Thin sheets of cellophane having thin opaque coatings of White modifiedink of the formula in column 3 above were used in the same manner andsimilarly examined. The letters were clearly transparent and under themicroscope fine white particles appeared to !be scattered throughout theimpacted areas.

Coating compositions wherein pigment is suspended in an aqueous vehiclesuch, for example, as the so-called water base inks used in themanufacture of wall paper, may similarly be modified and used in themanufacture of auto copy paper in accordance with my invention. Aqueouscoating compositions have the advantage that they may be applied to thepaper in the course of its manufacture by the ordinary paper coatingapparatus now employed for the manufacture of ordinary coated paper.

As an example of a white ink for application by the usual papercoating'machine the following formula is satisfactory:

I Parts Diethylerie glycol monostearate 90 Finelyprecipitated calciumcarbonate 10G Casein dissolved in ammonia water 18 Water 150 Many of thewater base inksand coating compositions how in use can be readilymodified so as to have autoebpy properties.

-A pigmented, water-base ink or coating composition for paper consists,in its simplest form, of a dissolved or colloidally dispersed solid,film-forming adhesive and a pigment which, when the water is removed,adheres to the fibrous paper base. The adhesive acts as a binder for thepigment particles so that these will not be picked oil the sheet in theprinting press. The pigment produces the desired color shade and makesthe paper surfacereceptive to printing ink. The coating operationconsists of laying down a continuous film of adhesive and pigment overthe individual fibers and filling the hollows between them. The relativeproportions of adhesive to pigment c'anbe varied, but in general, thepigment comprises from 75 to 90% by weight of the dry ingredients andthe adhesive comprises from to The watercontent ranges'frorn 70 to andconversely, the solids content of the coating or ink ranges from 30 to70%. The adhesives used are: starch, gums, glue, casein, vegetableproteins, water-soluble cellulose, latex and synthetic resins. Thepigments used are: clay, calcium carbonate, titanium dioxide, zincoxide, satin White, gloss white, and similar pigments derived fromcalcium, bari- "um, zinc, lead and the like.

In commercial practice, many coatings and inks are made with pigmentblends, such as, clay-calcium carbonate-titanium dioxide, and the like,in order to combine the desirable properties of two or more pigments.Adhesives, on. the other hand, are blended for inks but very seldom forcoatings, with the exception of latex which is widely used in coatingswith casein and in some In all cases, the major ingredients of thecoating formula, are the adhesive and the pigment. However, commercialcoatings and inks, always contain a number 'of other materials which areadded as minor ingredients. These materials are not an essential part ofthe coating mixture or ink, but are added for special 'efiects, mostlyto facilitate the application of the ink or the coating mixture by meansof high speed mechanical The materials commonly added as minoriiigr'cdicnts are: wax emulsions of carnauba, candelilla,

ceresin, japan, parafiin and beeswax, glycerin, glycol, sorbitol, cornsyrup, dextrin, yellow soap, castile soap, metallic soaps both solubleand insoluble, as sodium stearate, ammonium stearate, calcium stearateand the like, dispersing agents, in the order of sodium tctraphospirate,pyrophosphate, hexametaphosphate and ammonium caseinate and the like.Antifoaming agents in the order of octyl alcohol, fusel oil, pine oil,sulfonated oils and, finally, preservatives in the order of chlorinatedphenols, beta-naphtol and the like. The coating or ink composition isusually prepared by dispersing the blend of pigments and the adhesiveseparately in water and then mixing the two together.

The following are specific examples of formulas for producing aWater-base white pigmented ink for printing by rotogravure, and awater-base white pigmented coating composition for book paper forapplication by high speed roller coaters:

Water-base white ink:

White coating for book paper:

Pigment slurry Clay Calcium Cafbbfiafe 20 Sodium tetraphosphate 1 Wafer6D Adhesive vehicle solution- Wax emulsion 12% solids -e 2 Soap 2 Turkeyred oil 1 Enzyme converted starch 25 Water A reduction of thefilm-foaming adhesives used in the formulas given above, that is to say,the yellow dextrin, the gum arabic and the enzyme converted starchrespectively, plus the addition of a quantity of a solid,waterdispersible, non-ionic surface active agent, of melting point of 55to 70 degrees centi'grade and above, in the order of diethylene glycolmonos'tearate, glyceryl mono :palmitat'e, penta'erythritol tetrastearateand the like or combinations thereof, that will correspond on a poundper pound weight drybasis'with that of the pigment content in theformulas, is the only change required to produce a modified, water-basepigmented white ink and a modified, water-base pigmented white coatingcomposition which may be substituted for the unmodified ink and thecoating composition in the operation of the rotopress and the rollercoater, as the case may be, in order to produce auto copy papers.

Besides clay and the white pigments used in the for- "mulas referred toabove, there are many other pigments that may be used either alone or inblends which, in

conjunction with surface-active agents, will produce suitable, modified,water-base pigmented inks and coating compositions for making auto copypapers, exampies of these are: magnesium carbonate, magnesium oxide,magnesium silicate, barium carbonate, zinc sulphide, mica, talc,diatomaceous earth, silica, white low gelling bentonite, gloss white,satin white, silk white, blanc iixe and the like. In this connection,the following are typical specific examples of formulas forready-modified, wa-

te'r-bas'e pigmented coatings'which have been found sati'sfacto'ry forproducing auto copy papers.

Example A Pigment slurry: Parts Magnesium carbonate 100 Polyoxyethylenelauryl ether 0.1 Water 50 Binder vehicle solution:

Diethylene glycol monostearate 90 Beeswax l Polyoxyethylene stearate 0.1Water 450 Example B Pigment slurry:

Satin white 30 Water ground mica '10 Magnesium carbonate 60Polyoxyethylene alkyl lauryl ether 0.1 Water 50 Binder vehicle solution:

Polyethylene glycol stearate 90 Morpholine soap Carnauba wax 5Water-soluble cellulose 5 Water 450 Example C Zinc sulphide 2 Blanc fixeWhite bentonite 10 Talc 3 Magnesium carbonate 75 Polyoxyethylene laurylether 6.1 Water 50 Binder vehicle solution:

Glyceryl monopalmitate 90 Polyoxyethylene stearate Polyvinyl alcohol 1OPetroleum wax 10 Water 450 By virtue of the fact that the modified inksused in the manufacture of my improved auto-copy paper can be made inany color desired and can be printed on the paper or other sheet in anydesired pattern, in difierent colors and in overlying layers withunmodified inks, many difierent ty es and forms of auto-copy paper maybe made, some of which I have illustrated in the accompanying drawings.

FIG. 1 shows a sheet for making ordinary copies of typewritten material.The back of the sheet is preferably black or other dark color. On onesurface of this sheet is a coating of modified white ink compounded, forexample, in accordance with Formula No. 1 above and applied to thesurface of the sheet 1 by a paper coating machine of the roll coatertype. Instead of using dark paper and white modified ink, the sheet maybe of ordinary white paper as shown in FIG. 2, with a coating ofmodified ink of any desired color, for example, blue, such as producedby Formula 5 above. Any desired combination or" colors may be obtainedby printing the sheet with unmodified ink of the color desired for thewriting and then by a printing or coating operation, applying anoverlying layer of modified ink of the color desired for the unprintedareas. If desired, a copy on a transparent sheet may be made with copysheets such as shown in FIGS. 1 and 2 by using in the modified inksurface-active agents which effect the opacity of the ink in impactedareas intact as above described. Such a sheet is shown in FIG. 3.

For this purpose any thin transparent sheet material may be employed,such, for example, as cellophane, Pliolm, cellulose acetate, tracingpaper, glassine paper and the like. By interleaving the transparentsheet between the paper on which the written record is made and thefirst copy sheet there can be produced at one operation a typewrittenoriginal, a transparent sheet having the record in opaque letters, andas many copies as desired. The

. lfi transparent copy can be used for making photoprint copies of thedocument.

The surface of the transparent sheet may be treated to increase theadhesion of the detached coating composition by applying a weak solutionof nitrocellulose lacquer or the like or may be slightly roughened bysanding. Unless the surface is exceptionally hard and smooth asatisfactory transparent record can be made without treatment of thesurface of the sheet.

As the record on the transparent sheet is in reverse, sheets so made canbe used with advantage for address labels and the like. For this purposethe surface of the transparent sheet adjacent the copy sheet may betreated with an adhesive which serves not only to enhance the adhesionof the detached coating to the surface of the sheet, but also to stickthe sheet to the article to be labeled. The legend on the label is onthe underside of the transparent label and is thus protected againstmoisture, abrasion, etc.

In FIG. 4 I have shown an opaque sheet having a record in transparentletters. This sheet may be formed by printing a coating of modified inkon a transparent sheet, such for example, as glassine paper orcellophane. When a sheet of this character is placed beneath the paperin a typewriter the modified ink will be detached in the areas impactedby the keys. Such a sheet will produce a positive blue print orphotostat.

FIG. 5 shows a simple multicolor form particularly useful fortabulations in columns where it is desired to have each column appear ina distinctive color. Tabulated forms when so printed are much easier toread from the standpoint of speed and accuracy, and also as regards eyefatigue. As here shown each of the areas where figures forming theseveral columns are to be transcribed is printed with a difierentcolored modified ink, all of which may be readily applied at a singleoperation by a suitable multicolor press or by a paper coating machineequipped with striping rolls.

In the form of sheet shown in FIG. 6 the figures forming the diiferentcolumns appear in di'iferent colors and the different areas of the sheetalso appear in different shades so that each separate area stands outdistinctly whether or not figures are recorded therein. In this sheetthe separate areas are printed in separate colors with unmodified inksand the whole sheet is then overlaid with a thick coating of whitemodified ink which does not have sufiicient hiding power to completelymask the underlying colors. When a form of this kind is used the lettersand figures appear in the bright colors of the underlying coatings ofunmodified inks, the figures being surrounded by the unmodified whiteink which, however, in each area is difierently shaded by the underlyingcolor.

In the sheet shown in FIG. 7 the paper is uncoated white paper with acoating formed in part of unmodified ink and in part of modified ink. Arecord will be made only in those areas where the modified ink is used.By using modified and unmodified inks of the same color it cannot betold from an inspection of the copy whether or not there was any writingon the portions or" the ribbon copy sheet corresponding to the partsprinted with unmodified inks. To better conceal the line of demarkationbetween the areas printed in the different kinds of ink the printing ispreferably in the form of fine lines, as indicated.

in the sheet shown in. FIG. 8 the multi-color arrangement of FIG. 5 iscombined with the restricted copying feature of FIG. 7 In this sheet thedifferent columns are printed in difierent colors as in FIG. 5, butdifferent portions .of the columns are printed in part with modifiedinks and in part with unmodified inks. To better mask the lines or"demarkation between the areas printed with modified and unmodified inksthe printing is preferably in horizontal finely spaced lines as abovedescribed.

In FIG. 9 I have illustrated an auto-copy paper which dampness, heat andother external causes.

ll :giS particularly suitable for use in modern business machines.

fIt iswelllmown that the printing mechanism by which 'the recordis madein modern high speed electronic busi- '-ness machines for recording inmultiple copies, operates third of the striking force at the type faces911 an ordi- .cnary typewriter required to make five legible carboncopies on paper of the weight customarily employed for such purpose.Such machines, however, make 150 imv:pressions per minute, and theirusefulness would be ,greatly increased if more legible copies could bemade.

Machines operating at the high speeds above mentioned are verydestructive of ink ribbons. After a few hours continuous service theribbons are .so worn as to no longer make clean impressions. Thefrequentreplacement of the ribbons is in itself costly and timeconsuming. :Furthermore the lint from the frayedribbons adheres to thetype faces, necessitating frequent cleaning of the keys,

which adds greatly to the expense and time lost.

Any of the above-described auto-copy papers may be used in ribbonlessmachines for a brief period of operation, but the impact of the keys onthe coated surface of suchpaper results in particles of the coatingadhering --to the type face in the same manner as the lint of the{frayed ink ribbons so that although the cost of ribbons and theshut-down time incidental to changing the ribbon is saved by the use ofthe above-described paper, there is still the necessity of frequentlycleaning the type faces for the printing to continue to be clear anddistinct.

With the sheet of FIG. 9 the coating is not on the side of the sheetexposed to the impact, but on the reverse side, and the sheet is made ofmaterial from which nothing is detached in the printing operation. I

A thin sheet of glassine paper, cellophane or plain transparent tracingpaper of suitable formation and tensile strength, is coated on onesurfacewith a thin, even coat of a modified ink, for example, one of theformulas given in column 3.

I then print on the opaque layer of modified ink a backing layer ofunmodified ink of a color different from the color of the modified inkso that when the opacity of the modified ink in the areas impacted bythetype face is destroyed, thesurface of the backing layer so exposedwill make a clear and easily readable character against the surroundingareas where .the layer of modified ,ink is unaffected. The backing layerforming the outer coating on the transparent sheet over the coating ofthe modified ink and which constitutes the back of the sheet after thesheet is printed or written upon should be thin and flexible andtenaciously inherent so as to serve as a protective shield againstobliteration of the record by abrasion,

For this purpose I have found that the incorporation in the unmodifiedink of rubber-like materials which are themselves film-forming isadvantageous, so that in effect the resulting sheet is in the nature ofa sandwich with the layer of sensitive coating material between atransverse film on its top face and a backing film which will ordinarilybe colored with a color diiferent from that of the sensitive film. Forexample, this backing. film may consist of Victoria blue ink base 15parts; synthetic rubber Pliolite .resin No. -Sb, 5 parts; chlorinateddiphenyl No. 5420,

3 parts, toluol 92 parts.

A blue ink of this composition may be applied to the paper by a highspeed printing press in the same way as the layer of modified ink. Thesheet so produced is blue on one side and white on the other side andwith a transparent eoatiugover the white layer, this transparentcoatboth surfaces.

12 ing being in fact the sheet of glassine paper upon which the layersof modified and unmodified ink are appliedin the manufacture of thesheet.

The backing film may, however, be transparent if it is desired to have arecord wherein the characters are transparent to transmitted light. Forthispurpose the above composition may be used with the Victoria bluebase omitted. As explained above, such sheets are useful for makingdirect photostatic copies or for producing optical projectionsof thesheet.

The composition "forming the backing layer may be rendered opaque by theinclusion of pigments in the material as described, or the transparentlayer may be rendered opaque by dusting the applied layer with pigmentsin powder or flake-like form, such as aluminum, magnesium, bronze andthe like, to produce a continuous outer metallic surface in the order ofone fiakein thickness.

In addition to ,thepigment of a color different from that contained inthe modified ink I may, if desired, apply a third layer of coatingcomposition, either by way of dusting or otherwise, to the sheet, thethird layerbeing t'the same color as the modified ink in order that thesheet present on both sides the samecolor, for example, white.

The coating on thepaper of FIG. 9 may be applied as water base inks suchas above described. For example, the transparent sheet maybe coated witha thin, even coat of amodified, water-base white pigmented ink orcoating composition of the above. ExampleA, .B, ..or C and then dried.The dried white coating is.then.overcoated with a thin film .of anystandard unmodified water-base ink or pigmented coating composition .ofa contrasting color,

for example, black, dark blue or violet and the like.

jplasticized, suchas carboxymethyl cellulose, methyl cellulose,polyvinyl alcohol, converted starch, rubber latex,

Saran and the like. In fact, almost any water-soluble, water-dispersibleor emulsifiable, film-forming adhesive of combinations'thereof whichforms a film having sufificient strength to remain intact in unsupportedareas coextensive with the impressed characters maybe employed.

Also for the auto-copy sheet of FIG. 9 coatings of the prior art havingauto-copy properties may be used. The coating is not exposed andconsequently the properties of these prior art coatings whichrender themunsatisfactory for use on the exposed surface of a sheet do notpreventthe use of these coatings in a sheet such as shown in FIG. 9.

In 'FIG. 10 I have shown a three-sheet leaflet for use in recordingtransactions in which only the middle sheet has auto-copy properties.This middle sheet is coated on The sheet is preferably of dark coloredpaper and has on its top face a coating of white modified ink of aformula which does not adhere to the back of the overlying sheet in theimpacted areas. The coating on the back of the sheet is preferably ofthe same color as the sheet itself, and the coating is of a formula suchthat the pigment in the impacted areas will adhere to the sheetagainstwhich it is pressed and will therefore form a record on the thirdsheet which may be a printed form on paper or cardboard. This threesheetleaflet is suitable for most commercial transactions as it provides asheet for the purchaser, a sheet for the seller, and a third sheet foraccounting purposes.

In the foregoing specification I have described the auto-copy coatingsconsisting of, either aqueous or nonaqueous suspensions as applied byeither printing opera- 13 tions or by the conventional procedures andapparatus used in the manufacture of coated paper. The coatings, eitheraqueous or non-aqueous, may also be applied by casting. This method ofmanufacture is particularly sutiaole for making the sheet of FIG. 9. Inso making this sheet a transparent film-forming solution is firstapplied to the casting surface, which is usually a chromium plated drum,and after the film is formedbut while it is still adhering to the drum alayer of coating composition is applied to the exposed surface of thefilm on the drum and at the same time a backing web of thin paper ofcontrasting color is pressed against the coating composition.

'1" he above-described casting process is now used on a large scale inthe mannfiacture of colored paper wherein the pigmented coating iscovered with a transparent layer having a cast surface. By substitutingfor the conventional coating compositions now used coatings of thecompositions above described, the process may be used without otherchange in the manufacture of auto-copy paper of the type disclosed inFIG. 9.

Instead of applying a paper backing sheet to the coating on the drum,the transparent film formed on the drum surface may he made thick enoughto be self-sustaining and a backing layer of a composition such as usedin the manufacture of the sheet in the manner described in column may beapplied to the surface of the modified coating while still on thecasting drum.

The casting process may also be used with advantage in making the othertypes of auto-copy paper by substituting modified coatings for theconventional coatings used in the manufacture ofi cast-coated paper. Thecasting process provides a good printing surface without compacting thecoating composition as is necessary when the coating is calendered.

My improved auto-copy paper may be used with advantage in the recordinginstruments of telautographic systems by the substitution of anelectrically heated stylus for the pen or other marking instrument nowused for making the record on ordinary paper. Recording instrumentsusing ink are inherently a source of trouble, particularly where theinstrument is used at irregular intervals such that the pen standsmotionless for considerable periods of time. In such cases the ink tendsto thicken so that although the machine operates, no record is made.With an electrically heated stylus the machine is always in workingorder without attention, and with my improved copy paper consisting, forexample, of an underlying sheet of dark paper and an overlying layer ofthe formula given above as Example 1, a clear, permanent record will bemade on each operation of the machine, regardless of how long theintervening idle period.

I claim:

1. An auto-copy sheet comprising a backing sheet, a continuous opaquecoating of pigment particles and a binder containing a Wate -insolble,chemically inert, nonionic surface active agent on one surface of saidsheet, said coating being firm, dry and non-tacky and of a char actersuch that the impact of a typewriter key under normal operation destroysthe opacity of the coating in the impacted area and reveals the surfaceof the underlying sheet in such area.

2. The auto-copy paper of claim 1 wherein the backing sheet is paperwith its surface underlying the pigment of a color different from thecolor of the pigment layer.

3. The backing layer of claim 1 wherein the surfaceactive agent is takenfrom the class consisting of diethylene glycol monostearate, diethyleneglycol mon'opalmitate, pentaerythritol tetrastearate, glycerylmonomyristate, ethylene glycol monomyristate, polyethylene glycolmonostearate, glyceryl monopalmitate.

4. The auto-copy paper of claim 3 wherein the surfaceactive agent is amonostearate.

5. The auto-copy paper of claim 3 wherein the surfaceactive agent is aglycol monostearate.

6. The auto-copy paper of claim 3 wherein the surfaceactive agent isdiethylene glycol monostearate.

7. The auto-copy paper of claim 3 wherein the surfaceactive agent isglycol monomyristate.

8. The auto-copy paper of claim 3 wherein the surfaceactive agent ispentaerythritol tetrastearate.

9. An auto-copy sheet consisting of a transparent selfsustaining pliablefilm, an opaque coating of pigment particles and a binder containing awater-insoluble, chemically inert, non-ionic surface active agent on oneside of said film, said film being of a character to be renderedtransparent in limited area subjected to impact or pressure applied tothe opposite side of the transparent him, and a second layer of acontrasting color overlying the firshmentioned coating and of acharacter to be unaffected by such impact or pressure.

10. The auto-copy sheet of claim 9 wherein the backing layer is acontinuous layer of pigment particles and a bonding agent.

'11. The auto-copy sheet of claim 9 wherein the second layer is atransparent film.

12. The method of making the copy sheet of claim 9 which consists informing a transparent film on a casting drum, applying to the surface ofthe film while on the drum a thin layer consisting of pigment particlesand an agent for rendering the layer of pigment particles resulting fromthe evaporation of the liquid from the carrier susceptible to impact ofa typewriter key and thereafter applying to the surface of the coatingWhile on the drum :1 second coating of pigment particles and a bindingagent of a character to produce a layer which is not susceptible toimpact of a typewriter key.

13. The method of making the auto copy sheet of claim 1 which consistsin applying to the surface of a backing sheet a thin coating consistingof a liquid carrier containing a binder and pigment particles of colordifferent from that of the underlying surface and a Water insoluble,chemically inert, non-ionic surface-active agent for rendering the layerof pigment particles resulting from the evaporation of the liquid fromthe carrier susceptible to the impact of the typewriter key andthereafter drying said applied coating by pressing the coating layerWhile still plastic into adhering contact with the surface of a castingdrum.

14. An auto copy sheet comprising a base sheet and a coating ofcontrasting color adhering to at least a portion of the surface of saidsheet, said coating comprising pigment particles and a surface activeagent of a character to reduce the cohesion of the pigment particles andtheir adhesion to the underlying sheet to an extent that the cohesion ofthe particles and their adhesion to the carrier are destroyed by theimpact of average typewriter operation in an area co-extensive with thetype, said surface active agent consisting essentially of glycolmonostearate.

15. An auto copy sheet comprising a base sheet and a coating ofcontrasting color adhering to at least a portion of the surface of saidsheet, said coating comprising pigment particles and a surface-activeagent of a charactor to reduce the cohesion of the pigment particles andtheir adhesion to the underlying sheet to an extent that the cohesion ofthe particles and their adhesion to the carrier are destroyed by theimpact of average typewriter operation in an area co-extensive with thetype, said surface-active agent consisting essentially of diethyleneglycol monostearate.

16. An auto copy sheet comprising a base sheet and a coating ofcontrasting color adhering to at least a portion of the surface of saidsheet, said coating comprising pigment particles and a surface-activeagent of a character to reduce the cohesion of the pigment particles andtheir adhesion to the underlying sheet to an extent that the cohesion ofthe particles and their adhesion to the carrier are destroyed by theimpact of average typewriter operation in an area co-extensive with thetype, said surfacestate.

17. An auto copy sheet comprising a base sheet and a coating ofcontrasting color adhering to at least a portion of the surface of saidsheet, said coating comprising pigment particles and a surface-activeagent of a character to reduce the cohesion of the pigment particles andtheir adhesion to the underlying sheet to an extent that the cohesion ofthe particles and their adhesion to the carrier are destroyed by theimpact of average typewriter operation in an area co-extensive with thetype, said surface-active agent consisting essentially ofpentaerythritol tetrastearate.

References Cited in the file of this patent UNiTED STATES PATENTS WestOct. 11, l9l0 Bradner July 2, 1929 Mayer Dec. 2, 1930 Dixon Nov. 26,1935 Quick May 4, 1943 Newman May 23, 1950 Carter Oct. 17, 1950 BrewsterAug. 18, 1953

1. AN AUTO-COPY SHEET COMPRISING A BACKING SHEET, A CONTINUOUS OPAQUECOATING OF PIGMENT PARTICLES AND A BINDER CONTAINING A WATER-INSOLUBLE,CHEMICALLY INERT, NONIONIC SURFACE ACTIVE AGENT ON ONE SURFACE OF SAIDSHEET, SAID COATING BEING FIRM, DRY AND NON-TACKY AND OF A CHARACTERSUCH THAT THE IMPACT OF A TYPEWRITER KEY UNDER NORMAL OPERATIONSDESTROYS THE OPACITY OF THE COATING IN THE IMPACTED AREA AND REVEALS THESURFACE OF THE UNDERLYING SHEET IN SUCH AREA.